1. Field of the Invention
The present invention relates to fuel cell power plants.
2. Description of the Prior Art
As fuel cell power plants for producing electricity come closer to commercial reality more and more effort is being directed to improving the efficiency of the power plant and the cost of the power plant without the necessity for developing new and improved materials and components. One approach is to eliminate or reduce the size of existing components such as by altering the order of arrangement of components in an effort to make more efficient use of the available energy in various gas streams. Other techniques for improving efficiency and reducing cost may include modifying the operating parameters of the system. An example of efforts along both of these lines resulted in the power plant configurations shown and described in commonly owned U.S. Pat. No. 3,976,507. The power plant shown therein used pressurized reactants by incorporation of a turbocharger driven by what otherwise might have been wasted energy produced within the power plant. Coupled with the pressurizing of the power plant was the use of cathode gas space exhaust in a fuel reactor to produce hydrogen, the reactor exhaust being directed through various heat exchangers and thence through the anode gas space of the fuel cells. The anode exhaust, after increasing its temperature by passing it through a catalytic burner, was used to drive the turbocharger for compressing the air fed to the cathode gas space.
One advantage of the power plant described in the abovementioned U.S. patent is the elimination of water recovery apparatus because the steam needed by the reactor was present in the cathode effluent gases.
Despite the many advantages of the foregoing power plant it is not totally satisfactory. For example, any water liberated in the anode gas space exhaust is wasted in that it is not used in the reactor and therefore does not improve the performance of the reactor. Furthermore, a pressure drop across the reactor may result in a pressure imbalance across the fuel cell.